Background: I'm making an electronic drum for controlling PC keys. The drum circuit mainly uses a Pro Micro. In addition, I also made a light strip controller, using a Nano. The Pro Micro is powered by USB. During use the drum, the Nano may suddenly connect to the Pro Micro, and the Nano is powered by the Pro Micro via a 5V(Vcc) pin (actually USB powers both Arduinos at the same time).
Problem: At the moment the Nano is connected to the Pro Micro, there is a certain probability that the drum will not be able to control the PC after the connection.
My analysis:
a. Maybe the Pro Micro was disconnected from the UART of the PC. I re-plugged the USB and everything returned to normal.
b. The disconnection may be caused by a sudden drop in voltage when Nano is plugged in. I used an oscilloscope to test the voltage at the moment of connection: 5V→3V→5V. When the voltage drop is not so low (e.g., →3.5V), the Pro Micro and PC will not disconnect.
Help needed: How to solve this problem stably? Can a series resistor and capacitor between the Pro Micro's 5V and GND solve this problem?I am not sure how to choose the value of resistance & capacitance.
Post an annotated schematic showing how you have wired it. Flow charts though nice do not convey the needed information to solve your problem. Gil's Crispy Critter Rules for Processor Hardware:
Rule #1: An Arduino is NOT a Power Supply!
Rule #2: Never connect anything inductive (motors, speakers) directly to an Arduino!
Rule #3: Avoid connecting or disconnecting wires while the power is on.
Rule #4: Do not apply power to any pin unless you are certain of what you're doing.
Rule #5: Do not exceed the maximum voltage ratings.
Rule #6: Many Arduinos cannot power transmitters directly.
Rule #7: Before powering your project, take a break and double-check the wiring.
LaryD’s Corollaries:
Coro #1: When starting out, add a 220Ω resistor in series with both input and output pins to protect against shorts.
Coro #2: Invest in a Digital Multi-Meter (DMM) to measure voltages, currents, and resistance.
Note: Violating these rules can turn your Arduinos into crispy critters. For optimal performance, keep your wires under 25 cm (10 inches).
Additional Tips:
The L293 motor driver, though common, is inefficient as it can lose around 3V as heat when driving both legs of a motor. Consider using a motor driver with MOSFET outputs to reduce heat loss and conserve battery power.
